Studies will be continued on comparative aspects of Sindbis virus replication in arthropod and veterbrate cells. An explanation will be sought for why ribavirin is able to inhibit viral replication very efficiently in Aedes albopictus cells but poorly or not at all in BHK cells. Attempts will be made to find conditions under which ribavirin inhibits viral replication in BHK cells more efficiently. Sindbis and VSV mRNAs will be translated in cell-free lysates prepared from cultured A. albopictus cells, and the products will be characterized. Comparisons will be made between lysates prepared from uninfected cells and from virus-infected cells in order to determine how protein synthesis is inhibited in virus-infected Aedes albopictus cells. The synthesis of flavivirus proteins will be studied by labeling infected cell cultures as well as by attempting to translate dengue virus RNA in vitro. Sequence analyses of the 3' and 5' termini of dengue virus RNAs will be initiated using rapid RNA sequencing techniques.